would like info on setting timing on 1925 American LaFrance-12. 6 cylinder in line engine. Has Magneto and distributor. Where should the advance lever be positioned for setting timing? How many degree of timing does the engine require 34, 36, 38 degrees Before Top Dead Center. Should the engine be started with any of the compression valves opened? Need this info for a Christmas parade in Titusville, Fl. Thanks for any help. Richard Burns, fire Chief's father in law.